[Libguestfs] [RFC nbdkit PATCH 0/2] Add 'nbdkit nbd shared=1' mode

I got annoyed by qemu-nbd's default of only allowing a single connection; combine that with nbdkit's nbd plugin, and even 'qemu-nbd --list' of nbdkit counts as the single connection and immediately hangs up. If we introduce a shared mode, then 'qemu-nbd --list' can connect as many times as it wants without killing the original qemu-nbd wrapped by nbdkit. But this in turn required a way to wait for the socket to appear (as nbdkit --exit-with-parent has to be invoked before exec qemu-nbd, but the socket isn't created until the latter case). RFC in part because I wonder if nbdkit should offer a shared mode to ALL plugins, rather than just the nbd plugin providing its own. Eric Blake (2): nbd: Add retry=N parameter nbd: Add shared=true parameter plugins/nbd/nbdkit-nbd-plugin.pod | 22 ++++- plugins/nbd/nbd.c | 134 +++++++++++++++++++++--------- 2 files changed, 115 insertions(+), 41 deletions(-) -- 2.20.1